1. Field of the Invention
The invention relates to the production of aminoalkylalkoxy-silanes from the corresponding halo(haloalkyl)silanes by reaction with ammonia or organic amines and with alcohol.
2. Description of the Related Art
Aminoalkylalkoxysilanes are important intermediates in the industry. The amine functionality permits linking with further synthesis building blocks, for example for the formation of copolymers. Alkoxy groups on the silicon assume the function of binding to polysiloxane backbones.
Starting materials for the synthesis of the aminoalkylalkoxysilanes are usually the corresponding alkoxy(haloalkyl)silanes, which are converted to the aminoalkylalkoxysilanes using ammonia or organic amines. The alkoxy(haloalkyl)silanes required as chemical precursors for the amination are produced in the procedure via a separate, independent alkoxylation procedure.
Both alkoxylation and amination are each technically complex methods which can only be carried out in special apparatus. The alkoxylations require apparatus resistant to halohydric acids. Secondary reactions, for example, formation of water during reaction of alcohol with formed hydrogen halide to give alkyl halide can only be prevented by special methods, e.g. countercurrent methods, which ensure that hydrogen halide is removed quickly from the reaction mixture. DE 60315982 T2 equivalent to U.S. Pat. No. 7,659,418, describes, for example, an apparatus for producing 3-chloropropylalkoxysilanes from the corresponding chloro(3-chloropropyl)silanes according to the countercurrent principle. JP 2003246789 describes the use of ammonia or organic amines in the alkoxylation, but this serves only for the removal of hydrogen chloride during the synthesis of the corresponding alkoxychloroalkylsilanes.
Animations, by contrast, require apparatus apparatus which is stable in basic environments. Due to low boiling point of especially ammonia and low molecular weight amines, these reactions are carried out industrially in steel autoclaves, in most cases under high pressure, to achieve short reaction times and/or high conversion. Fundamental work on this is described by Speier et al. in J. Org. Chem. 1971, 36, 3120-3126. Furthermore, aminoalkylalkoxysilanes—as likewise reported in J. Org. Chem. 1971, 36, 3120-3126—can be obtained by alcoholysis of silazanes.
DE 2521399, equivalent to U.S. Pat. No. 4,045,460, describes the synthesis of aminoalkylalkoxysilanes proceeding from tri- and dialkoxy(chloroalkyl)silanes in the presence of alcohol as solvent addition. The added alcohol does not participate in the reaction but serves only as an inert additive. The starting material is the corresponding alkoxysilanes which have been produced via an independent reaction step.